School of Mathematicshttp://hdl.handle.net/2262/1
School of Mathematics

2015-08-02T22:27:44ZCacti and filtered distributive lawshttp://hdl.handle.net/2262/73949
Cacti and filtered distributive laws
DOTSENKO, VLADIMIR
Motivated by the second author’s construction of a classifying space for the group of
pure symmetric automorphisms of a free product, we introduce and study a family of
topological operads, the operads of based cacti, defined for every pointed simplicial
set
.
Y
;
p
/
. These operads also admit linear versions, which are defined for every
augmented graded cocommutative coalgebra
C
. We show that the homology of the
topological operad of based
Y
–cacti is the linear operad of based
H
.
Y
/
–cacti. In
addition, we show that for every coalgebra
C
the operad of based
C
–cacti is Koszul.
To prove the latter result, we use the criterion of Koszulness for operads due to the
first author, utilising the notion of a filtered distributive law between two quadratic
operads. We also present a new proof of that criterion, which works over a ground
field of arbitrary characteristic
PUBLISHED
2015-01-01T00:00:00ZQuark-gluon plasma phenomenology from the latticehttp://hdl.handle.net/2262/73781
Quark-gluon plasma phenomenology from the lattice
RYAN, SINEAD
The FASTSUM Collaboration has calculated several quantities relevant for QCD studies
at non-zero temperature using the lattice technique. We report here our results for the (i)
interquark potential in charmonium; (ii) bottomonium spectral functions; and (iii) electrical
conductivity. All results were obtained with 2+1 flavours of dynamical fermions on an
anisotropic lattice which allows greater resolution in the temporal direction.
PUBLISHED
2014-01-01T00:00:00ZThe bottomonium spectrum at finite temperature from N f = 2 + 1 lattice QCDhttp://hdl.handle.net/2262/73780
The bottomonium spectrum at finite temperature from N f = 2 + 1 lattice QCD
RYAN, SINEAD
We present results on the bottomonium spectrum at temperatures above and
below the deconfinement crossover temperature,
T
c
, from dynamical lattice QCD simu-
lations. The heavy quark is treated with a non-relativistic effective field theory on the
lattice and serves as a probe of the hot medium. Ensembles with a finer spatial lattice
spacing and a greater range of temperatures below
T
c
than those previously employed by
this collaboration are used. In addition, there are
N
f
= 2 + 1 flavours of Wilson clover
quark in the sea with
M
π
≈
400 MeV and we perform a more careful tuning of the bottom
quark mass in this work. We calculate the spectral functions of S and P wave bottomonium
states using the maximum entropy method and confirm earlier findings on the survival of
the ground state S wave states up to at least 2
T
c
and the immediate dissociation of the
P wave states above
T
c
PUBLISHED
2014-01-01T00:00:00ZQuark-Gluon Plasma: From lattice simulations to experimental resultshttp://hdl.handle.net/2262/73779
Quark-Gluon Plasma: From lattice simulations to experimental results
RYAN, SINEAD
Theoretical studies of quarkonia can elucidate some of the important properties of
the quark–gluon plasma, the state of matter realised when the temperature exceeds
O
(150) MeV,
currently probed by heavy-ion collisions experiments at BNL and the LHC. We report on our
results of lattice studies of bottomonia for temperatures in the range 100MeV
T
450MeV,
introducing and discussing the methodologies we have applied. Of particular interest is the
analysis of the spectral functions, where Bayesian methods borrowed and adapted from nuclear
and condensed matter physics have proven very successful
PUBLISHED
2014-01-01T00:00:00Z